Low-cost wavelength division multiplexed (WDM) coupler with more flexible and precise optical faith adjustment

Abstract

The present invention discloses an improved wavelength division multiplexed (WDM) coupler. The WDM coupler includes a WDM filter attached to a first GRIN lens by applying a first heat-curing epoxy. The WDM coupler further includes the first GRIN lens inserted and fixed into a first holding tube by applying a second heat-curing epoxy. The WDM coupler further includes a second holding tube holding a dual fiber pigtail. The dual fiber pigtail is disposed at a first optimal position from the first GRIN lens to achieve a lowest reflection loss with the first and second holding tubes being in contact with each other. The dual fiber pigtail and the first and second holding tubes are fixed together by applying a third heat-curing epoxy. The WDM coupler further includes a second GRIN lens inserted and fixed into a third holding tube by applying a fourth heat-curing epoxy. The WDM coupler further includes a fourth holding tube holding a standard single fiber pigtail. To achieve a lowest transmission loss, the single fiber pigtail is disposed at a second optimal position from the second GRIN lens while the first GRIN lens is disposed at a third optimal position from the second GRIN lens. With the first, third and fourth holding tubes being in contact with each other, a fifth heat-curing epoxy is applied to fix the third and fourth holding tubes together and a sixth heat-curing epoxy is applied to fix the first and third holding tubes together.

I claim:  
     
       1. An optical device includes a plurality of optical parts for processing an optical signal transmission therein, comprising: 
       a plurality of gaps each having an adjusted distance between said plurality of optical parts;  
       two holding tubes holding two of said plurality of optical parts and said holding tubes are in contact with each other in at least one of said gaps;  
       at least one of said holding tubes is arranged to dispose at a slightly different vertical position than other holding tubes for aligning with an outgoing orientation of said optical signal transmission;  
       an epoxy applied over a contact area between two of said holding tubes over one of said gaps for securely bonding said holding tubes and said plurality of optical parts;  
       a WDM coupler wherein said WDM coupler further comprising:  
       a first GRIN lens attached to a WDM filter via a first epoxy;  
       a first holding tube holding and securely bonding to said first GRIN lens with a second epoxy;  
       a dual optical fiber pigtail disposed at a first optimal gap from said first GRIN lens to achieve a lowest transmission loss;  
       a second holding tube holding and securely bonding to said dual optical fiber pigtail with a third epoxy and said first and second holding tubes being further securely bonding to each other with a fourth epoxy for maintaining said optimal gap between said first GRIN lens and said dual fiber pigtail;  
       a third holding tube holding and bonding to a second GRIN lens with a fifth epoxy;  
       a fourth holding tube holding a single fiber pigtail disposed at a second optimal distance from said second GRIN lens said fourth tube securely boding to said single fiber pigtail and to said third holding tube with a sixth epoxy for maintaining said second optimal distance; and said first holding tube holding said first GRIN length in physical contact and securely boding to said third holding tube holding said second GRIN lens with a seventh epoxy wherein said WDM filter is aligned with said second GRIN lens and said single and dual fiber pigtails having aligned outgoing orientation.  
     
     
       2. The optical device of  claim 1  wherein: 
       said first, second, third, fourth, fifth, sixth and seventh epoxies are a 353ND epoxy.  
     
     
       3. The optical device of  claim 1  wherein: 
       said first and second holding tubes are a first and a second glass tubes.  
     
     
       4. The optical device of  claim 1  wherein: 
       said first and second holding tubes are a first and second holding tubes having a length ranging from 3.0 to 6.5 mm with an inside diameter of about 1.8 mm and an outside diameter of about 2.8 mm.  
     
     
       5. The optical device of  claim 1  wherein: 
       said third and fourth holding tube are glass tubes.  
     
     
       6. The optical device of  claim 1  wherein: 
       said third holding tube is a holding tube having a length of about 4.0 to 5.5 mm and said fourth holding tube having a length ranging from 2.5 to 3.5 mm and said third and fourth holding tubes having an inside diameter of about 1.8 mm and an outside diameter of about 2.8 mm.  
     
     
       7. The optical device of  claim 1  wherein: 
       said first and said second GRIN lens are GRIN lenses of 0.23 pitch.  
     
     
       8. The optical device of  claim 1  wherein: 
       said fourth holding tube holding said single fiber pigtail is arranged slightly lower than said third holding tube for achieving an aligned outgoing orientation with said dual fiber pigtail.  
     
     
       9. An optical device includes a plurality of optical parts for processing an optical signal transmission therein, comprising: 
       a plurality of gaps each having an adjusted distance between said plurality of optical parts;  
       two holding tubes holding two of said plurality of optical parts and said holding tubes are in contact with each other in at least one of said gaps;  
       at least one of said holding tubes is arranged to dispose at a slightly different vertical position than other holding tubes for aligning with an outgoing orientation of said optical signal transmission; and  
       an epoxy applied over a contact area between two of said holding tubes over one of said gaps for securely bonding said holding tubes and said plurality of optical parts.  
     
     
       10. The optical device of  claim 9  wherein: 
       said holding tubes over at least one of said gaps between said optical parts are glass holding tubes.  
     
     
       11. The optical device of  claim 9  wherein: 
       said epoxy applied over said contact area between two of said holding tubes over one of said gaps for securely bonding said holding tubes holding said plurality of optical parts are heat-curing epoxies.  
     
     
       12. The optical device of  claim 11  wherein: 
       said heat-curing epoxies are heat-curing epoxies of 353ND epoxies.  
     
     
       13. The optical device of  claim 9  wherein: 
       one of said optical parts is a dual fiber pigtail and one of said optical parts is a single fiber pigtail wherein said single and dual fiber pigtails having an aligned outgoing orientation.  
     
     
       14. An optical device includes a plurality of optical parts for processing an optical signal transmission therein, comprising: 
       a plurality of gaps each having an adjusted distance between said plurality of optical parts;  
       two holding tubes holding two of said plurality of optical parts and said holding tubes are in contact with each other in at least one of said gaps;  
       at least one of said holding tubes is arranged to dispose at a slightly different vertical position than other holding tubes for aligning with an outgoing orientation of said optical signal transmission;  
       an epoxy applied over a contact area between two of said holding tubes over one of said gaps for securely bonding said holding tubes and said plurality of optical parts;  
       a WDM coupler wherein said WDM coupler further comprising:  
       a dual fiber collimator held in a first holding tube; and  
       a single fiber collimator includes a GRIN lens held in a second holding tube and a single fiber pigtail held in a third holding tube wherein said first holding tube and second holding tube are in contact and bonded with an epoxy and said third holding tube disposed at a slightly different vertical position from said second holding tube to achieve an aligned outgoing orientation between said single fiber pigtail and said dual fiber collimator.  
     
     
       15. The optical device of  claim 14  wherein: 
       said third holding tube is disposed slightly below said second holding tube.  
     
     
       16. The optical device of  claim 14  wherein: 
       said first, second and third holding tubes are glass holding tubes.  
     
     
       17. The optical device of  claim 14  wherein: 
       said epoxy is a heat-curing epoxy.